表格post提交方式，form post method, form submit 提交 拦截

有人在stackoverflow上提过类似的问题访问

When you make a POST request, you have to encode the data that forms the body of the request in some way.

HTML forms provide two methods of encoding. The default is application/x-www-form-urlencoded, which is more or less the same as a query string on the end of the URL. The other, multipart/form-data, is a more complicated encoding but one which allows entire files to be included in the data. (HTML 5 introduces the text/plain encoding which is useful only for debugging … and even then the others are better given sensible debugging tools).

The specifics of the encodings don’t really matter to most developers.

When you are writing client-side code: Use multipart/form-data when your form includes any elements.

When you are writing server-side code: Use a prewritten form handling library (e.g. Perl’s CGI->param or the one exposed by PHP’s $_POST superglobal) and it will take care of the differences for you. Don’t bother trying to parse the raw input received by the server.

form submit 拦截

在手机上开发的时候，我们常常会使用html5的 input 元素的form属性来进行构建页面， 将form和输入控件分离开来，如下：

<form id="search-hack-form" hidden>
    <input id="search-hack-form-submit" type="submit" style="display: none"/>
</form>

<section id="search-bar" class="search-bar">
    <div class="search-box-container">
        <input id="search-box" class="search-box" form="search-hack-form" type="search"/>
    </div>
</section>

input#search-box 本来应该放在form中，但是我们把form单独抽离出来以使结构更加简单，清晰，而对于提交事件的处理，我们常常是采用监听submit事件的方式来实现：

// 拦截 search-box 的搜索行为
$("search-hack-form").addEventListener("submit", function (event) {
});

但是如果我们想在程序中主动的触发form的submit事件，比如说调用$(“search-hack-form”).submit(); 那么我们前边写的对submit事件的监听并不会得到执行，那怎么办呢？

方法也很简单，像我们上边的写法，在form中添加一个不可见的 search-hack-form-submit submit 的input元素，调用这个元素的click事件即可。

这个click事件会转而引发 form的submit事件。